A state-of-the-art analysis of the dwarf irregular galaxy NGC 6822

We present a detailed photometric study of the dwarf irregular galaxy NGC 6822 aimed at investigating the properties of its stellar populations and, in particular, the presence of stellar radial gradients. Our goal is to analyse the stellar populations in six fields, which cover the whole bar of this dwarf galaxy. We derived the quantitative star formation history (SFH) of the six fields using the IAC method, involving IAC-pop/MinnIAC codes. The solutions we derived show an enhanced star formation rate (SFR) in Fields 1 and 3 during the past 500 Myr. The SFRs of the other fields are almost extinguished at very recent epochs and. We study the radial gradients of the SFR and consider the total mass converted into stars in two time intervals (between 0 and 0.5 Gyr ago and between 0.5 and 13.5 Gyr ago). We find that the scale lengths of the young and intermediate-to-old populations are perfectly compatible, with the exception of the young populations in Fields 1 and 3. The recent SF in these two fields is greater than in the other ones. This might be an indication that in these two fields we are sampling incipient spiral arms. Further evidence and new observations are required to prove this hypothesis. In addition, we derived the age-metallicity relations. As expected, the metallicity increases with time for all of the fields. We do not observe any radial gradient in the metallicity.Comment: 9 pages, 11 figures, Accepted to A&

Functional Requirements Identification Using Item-to-Item Collaborative Filtering

One of the most difficult tasks in the development of software is the identification of the functional requirements. A well-defined functional requirement will eventually map the success of a software project. A support tool that can recommend candidate functional requirements for a software project being developed will help software engineers to deliver the right software to the clients.The purpose of this study is to determine whether a collection of previously developed software applications can serve as basis for the development of a model to identify functional requirements of a project to be developed. Completed software project documentations of Master in Information Technology graduates from Higher Education Institutions in northern Luzon were collected and categorized, and projects on Faculty Evaluation Systems were analyzed in order to extract the vectors of functional requirements for the target software domain. Item-to-item collaborative filtering is then applied to these vectors to form the recommender model. Finally, the model was validated using the leave-one-out cross-validation technique. The resulting high accuracy rate indicates that the model built using the item-to-item collaborative filter may be used to build a tool that can automatically recommend important related functional requirements given one or more requirements identified by any of the project stakeholders

Impacto da legislação na bioprospecção de plantas animaláricas a partir do etnoconhecimento nos estados do Amazonas e Acre.

A ?Rede de pesquisas de compostos químicos vegetais para o controle de malária a partir da etnofarmacologia nos estados do Amazonas e Acre? tem a participação de 11 instituições brasileiras e estuda, a partir do conhecimento de populações tradicionais da região amazônica, plantas antimaláricas com estudos in vitro

Amargor em plantas antimaláricas utilizadas na região de Barcelos (Amazonas, Brasil).

Neste trabalho foram estudadas as plantas medicinais utilizadas no tratamento da malária e males associados a partir do conhecimento de populações tradicionais da região de Barcelos, no Estado do Amazonas, Brasil

Vortices on demand in multicomponent Bose-Einstein condensates

We present a simple mechanism to produce vortices at any desired spatial locations in harmonically trapped Bose-Einstein condensates (BEC) with multicomponent spin states coupled to external transverse and axial magnetic fields. The vortices appear at the spatial points where the spin-transverse field interaction vanishes and, depending on the multipolar magnetic field order, the vortices can acquire different predictable topological charges. We explicitly demonstrate our findings, both numerically and analytically, by analyzing a 2D BEC via the Gross-Pitaevskii equation for atomic systems with either two or three internal states. We further show that, by an spontaneous symmetry breaking mechanism, vortices can appear in any spin component, unless symmetry is externally broken at the outset by an axial field. We suggest that this scenario may be tested using an ultracold gas of $^{87}$Rb occupying all three $F = 1$ states in an optical trap.Comment: 11 pages, 9 figures, (Accepted in PRA

Efficiency of Artificial Insemination at Natural Estrus in Organic Churra Ewes

Hormonal treatments used in the artificial insemination (AI) of sheep can cause several physiological problems that can affect negatively fertility and animal health; however, AI protocols based on the detection of natural estrus offer a more sustainable option and can achieve high fertility. In this study, an AI protocol at natural estrus in organic Churra sheep was performed. In the first phase (AI protocol development), 125 ewes were exocervically inseminated, and their fertility was assessed based on the following factors: number of AI, physiological state, body condition, estrus detection–AI interval, and vaginal fluids in cervix. That protocol was repeated for six consecutive years. In all individuals, fertilities based on the timing of insemination after estrus detection were very high. Lactating ewes produced better results than did dry ewes, which was probably because of the better feeding of the former. In addition, double insemination increased the fertility of ewes whose estrus was detected within 16 h of onset. Body condition and amount of vaginal fluid were correlated with fertility. Exocervical inseminations at natural estrus can produce acceptable fertility and prolificity in Churra ewes

Problemas en la hibridación interespecífica del género phaseolus: aborto del embrión. ensayo preliminar de cultivo de embriones

Los programas de mejoramiento del fríjol común (P. vulgaris) han encontrado limitantes en la estrecha variabilidad del acervo genético primario de esta especie (el cual incluye las formas cultivadas, mejoradas o no) para resistencia o tolerancia a enfermedades e insectos, así como a factores climáticos adversos. Debido a estos limitantes, los mejoradores han empezado a estudiar la posibilidad de transferir genes de otros acervos genéticos del género (secundarios, terciarios y aun cuaternarios) sin embargo esto implica la superación de algunas barreras genético fisiológicas. El presente trabajo es la base preliminar de un proyecto a largo plazo (3 - 5 años) de cruces interespecíficos a nivel de especies cultivadas del género Phaseolus: P. vulris, P. acutifolius, P. coccineus y P. lunatus. Su objetivo principal es el encontrar metodologías prácticas que permitan la hibridación interespecíficos.The breeding programs of the common bean (P. vulgaris) have met many restrictions which make difficult an increase in yield. Theses limitations refer to the narrow variability found in the primary pool of this species (which includes all the cultivated forms, improves of not) of resistance or tolerance to diseases and insects, such as the resistance to adverse environmental conditions. Because of all these limitations, breeders have begun to study the possibility of transfering genes from others genetic pools of the same genus (secondary, tertiary and even quaternary). This project is the preliminary basis of a long-term project (3 - 5 years) of interspecific crosses between cultivated species of the genus Phaseolus. Its main purpose is to find practical methodologies that will permit interspecific hibridization